Hi, my name is John. I live in Mesa, Arizona, and have been growing orchids for 20 years (though much more successfully while living in New York State!). Due to my struggle with growing orchids in Arizona I have had to learn to love desert plants and have a nice collection of frankincense and myrrh plants. Living in Arizona I have to deal with low humidity and intense sun and heat, all detrimental to orchids. I have decided to build a growing case to control all those factors and I need help deciding on which kind of grow lights to use. It is sad with all the sun we get in Arizona that I even need to consider artificial lighting but allowing the sun through the windows in the summer months raises the temps and AC bills. Also I have no east windows and one north window which allows a peak of 1000 ft candles of light through.
I would like to grow a variety of paphs and phrags under lights. Also I would like the lighting fixture to be at least two to three feet above the plants(ideally about 4' to 5') to allow for flower spikes and to enhance displaying the case in my living room. I don't know what all my choices for lighting are but so far I have found full spectrum flourescent, HO T5 flourescent, sodium and metal. I really don't want the heat associated with the sodium and metal types even though they can be set farther away from the plants. I was wondering how far away the full spectrum flourescents can be kept above the plants as well as the HO T5 flourescents? It doesn't seem there is a full spectrum tube available for the HO T5 flourescents which seems a drawback to me since the literature suggests using a mixture of cool and warm color tubes. Has anyone had experience with this type? I would appreciate any and all help. I am rather skeptical of artificial lighting. The only experience I have had was when I was younger in the 1970s and my dad tried to grow vegetables in the winter in the basement. All I can remember was spindly, weak, yellow tomato plants that couldn't stand up. I hope technology has advanced quite a bit.
Many thanks in advance for all the help!

Hi John! Welcome to the slipper forum! I don't use artificial lights but lots of our members do and some even grow orchids in Arizona. Members are here very helpful and friendly. What Paphs and Phrags are you planning to grow?

Hi John welcome to the forum glad you joined us!

How much square footage footprint are you talking? 6 square feet?

I suggest a 250 watt metal halide with remote ballast.

Not thinking 5' above the plants is feasible. For that distance a 400 watt metal halide would be best. That would be enough for 9 square feet, and even still probably 3-4 feet above the plants. You could do 250 watt but would need to keep it more like 2-3' over the plants. That would be for 6 square feet. I have not used T-5s but even for HID lamps 5' above the plants is too far away so I'm not thinking T-5s will work at that distance either. Of course it depends on if you are growing low- or high-light orchids. I have heard many have had success with the T-5s but they will need to be fairly close.

Metal Halide lamps grow beautiful, luxurious plants. The total opposite of the poor tomato plants from your childhood! Metal Halide has the best spectrum for orchid growth, which of course leads to great flowering.

If you have an external ballast it will keep the heat down in the enclosure. You will want to humidify the enclosure too but also allow for air exchange. Looking forward to seeing your final set-up!

Thanks for the welcomes. I am growing a few parvi's and their hybrids. I have a Phrag Jason Fischer and would like to add a few of the phrag species notably the long petaled ones and some of the multifloral paphs. I have several delenatii varieties and am always looking for a new variety. It is my favorite. IMHO you cannot beat its ease to grow, the fragrance, the color, nor its multifloral tendencies. If I had the space I would grow a whole 2' x 4' bench with just that species. BTW anyone know where I could get my hands on just one delenatii var. dunkel? My first love and greatest love of the plant world however are the Cypripediums. Where I grew up in New York C. acaule and C. parviflorum grew wild. The spring wild flowers there make me want to move back ie: trilliums, trout lilies, violets and yes even the dreaded dandelions. Even the weeds die here in the Arizona summers! Though the spring wildflowers are in exceptional color right now.
To answer Justin, I am hoping to build a case with a 2' x 4' foot print, thus 8sq ft. with a rectangular footprint to put along a wall, however I could build a 3' x 3' square foot print for a corner. Do the metal halides illuminate a rectangular or square footprint? What kind of heat do the bulbs and also the ballasts give off? Do you think I could grow phrags and parvis with a 250W metal halide at 3'? The 400W sounds like the ticket however does it generate noticeably more heat than the 250W? My concern is how the lights will affect my AC bill in the summer.
Can anyone comment on the HO T5 flourescent and the maximum distance they can be kept above the plants and if they make a full spectrum T5 bulb? Also if someone who has used both T5 and metal halide tell me which they prefer and why?

:hi::welcomesof:

Hi John:

For the space and kind of plants you describe, sounds like a 250 metal halide is exactly what you need. I think a 400 would be overkill in your situation, and the electric bill/heat is much lower with a 250.

For visualization, here's how I use my 250 metal halide, about 2+ feet above my plants.The foot print of this shelf is 2' x 4'. This would work great with no window too.

Justin

http://img150.imageshack.us/img150/1872/4x2hk3.th.jpg (http://img150.imageshack.us/my.php?image=4x2hk3.jpg)

John, I grow with T-5 HO 48 inch bulbs. They put out a lot of light. Mine are appox 40 inches above the grow table, and my plants flower with out problems. I use regular bulbs. They run at 95 degrees F vs. 77 degrees F for the T-8's. Rusty

John,

it sounds like you have air conditioning, so using a small, portable evaporative cooler will help cool the heat from the lights and add some humidity to the house.

The bad news is that you'll have to keep re-filling it.

I also grow with T5's and I think they do the job welll. How ever I would recommend that you keep these lights at least 20 inch above the top of your plants. I say this because I put my plants to close and the leaves turned a yellow-green color. At some point I plan on down grading my lights to a 2 bulb setup.